Combination oven



FIG. 1 is a front perspective view of the design of the combinationoven;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a right side elevational view with the left side being amirror image thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

The broken lines shown are for illustrative purposes only and form nopart of the design claimed.

The ornamental design for a combination oven, as shown and described.